Hitherto, in a line supplying a fluid from a main flow passage in a branched manner in a slurry line in the semiconductor industry or various chemical liquid lines, and in a line supplying a fluid from a main flow passage in a branched manner and circulating the fluid, for the purpose of preventing from occurrence of troubles, such as the condensation/solidification of a slurry or the depositing of crystals and the like, there has been often provided a line for cleaning the branched flow passage.
In such case, generally, there have been adopted a method of combining two two-way valves 55, 56 and two T-pipes 53, 54 as shown in FIG. 17, a method of combining a three-way valve 65, a two-way valve 61 and a T-pipe 60 as shown in FIG. 18, a method of combining three two-way valves 154, 156, 157 and two T-pipes 153, 155 as shown in FIG. 19, and a method of combining a three-way valve 162, two two-way valves 164, 165 and a T-pipe 163 as shown in FIG. 20.
However, in the case shown in FIG. 17, there are caused a problem that a chemical liquid stagnates in the flow passage from the T-pipe 53 to the two-way valve 55 and a problem that the flow passage from the two-way valve 55 to the T-pipe 54 is not sufficiently cleaned when cleaning. Also, in the case shown in FIG. 18, there is similarly caused a problem that the flow passage from the three-way valve 65 to the T-pipe 60 is not sufficiently cleaned.
Further, in the case shown in FIG. 19, there are caused a problem that a chemical liquid stagnates in the flow passage from the T-pipe 53 to the two-way 54 and a problem that the flow passage from the two-way valve 154 to the T-pipe 155 is not sufficiently cleaned when cleaning. Also, in the case shown in FIG. 20, there is similarly caused a problem that the flow passage from the three-way valve 162 to the T-pipe 163 is not sufficiently cleaned.